Safety seats or other restraint systems suitable for protecting young children from injury during transport in moving vehicles have, in the past, taken many forms. Generally adapted for transport in automobiles, the restraint devices have been bulky and cumbersome to relocate once installed into the automobile. Such existing seat safety structures are difficult to use when a child is to occupy an aircraft seat and cannot be conveniently stored, because the construction does not permit integration of individual seat-type restraints into a volume less than a multiple of the volume required by each restraint.